Editing Coral (section)

===Aquaria===
{{main|Reef aquarium}}
[[File:Zoanthus-dragon-eye.jpg|right|thumb|This dragon-eye zoanthid is a popular source of color in reef tanks.]]
The saltwater fishkeeping hobby has expanded, over recent years, to include [[Reef aquarium|reef tanks]], fish tanks that include large amounts of [[live rock]] on which coral is allowed to grow and spread.<ref>[http://www.advancedaquarist.com/2011/1/corals Aquarium Corals: Collection and Aquarium Husbandry of Northeast Pacific Non-Photosynthetic Cnidaria] {{Webarchive|url=https://web.archive.org/web/20170606164618/http://www.advancedaquarist.com/2011/1/corals |date=2017-06-06 }}. Advancedaquarist.com (2011-01-14). Retrieved on 2016-06-13.</ref> These tanks are either kept in a natural-like state, with algae (sometimes in the form of an [[algae scrubber]]) and a deep sand bed providing filtration,<ref>[http://reefkeeping.com/issues/2008-10/newbie/index.php Reefkeeping 101 – Various Nutrient Control Methods]. Reefkeeping.com. Retrieved on 2016-06-13.</ref> or as "show tanks", with the rock kept largely bare of the algae and [[microfauna]] that would normally populate it,<ref>[http://saltaquarium.about.com/od/aquariummaintenancecare/a/sandlrcleaning.htm Aquarium Substrate & Live Rock Clean Up Tips] {{Webarchive|url=https://web.archive.org/web/20160806201853/http://saltaquarium.about.com/od/aquariummaintenancecare/a/sandlrcleaning.htm |date=2016-08-06 }}. Saltaquarium.about.com. Retrieved on 2016-06-13.</ref> in order to appear neat and clean.

The most popular kind of coral kept is [[soft coral]], especially [[zoanthid]]s and mushroom corals, which are especially easy to grow and propagate in a wide variety of conditions, because they originate in enclosed parts of reefs where water conditions vary and lighting may be less reliable and direct.<ref>[http://marinebio.org/oceans/coral-reefs.asp Coral Reefs] {{webarchive|url=https://archive.today/20130625040003/http://marinebio.org/oceans/coral-reefs.asp |date=2013-06-25 }}. Marinebio.org. Retrieved on 2016-06-13.</ref> More serious fishkeepers may keep small polyp [[stony coral]], which is from open, brightly lit reef conditions and therefore much more demanding, while large polyp stony coral is a sort of compromise between the two.